It is known as disclosed in U.S. Pat. No. 4,837,910 to assemble needle bearings into an annular layer array using a mandrel to insert the array into a cylindrical opening in a receiving machine. The mandrel is centered within the bore of a recover block to define an annular space into which a discrete number of needle bearings are singularly fed from a specially configured track which holds the vertical serpentine column of needle bearings. A push rod engages the column to positively force a discrete number of bearings into the space while a grease packing is inserted about the bearings as they fill the space. After the bearings are positioned about the mandrel and grease has been injected about the needle bearings, the mandrel is moved axially to transfer the bearings into the hub of a gear. The bearings are held in place by the grease, but may still become dislodged during transport of the bearings. Thus, it remains desirable to provide an improved method and apparatus for assembling and retaining needle bearings in the cylindrical opening of gears, bearings, joints and the like.